JULY 8, 2002---When it comes to preparing soil for planting, tilling isn’t always the answer. In fact, those sharp, rapidly spinning tiller blades may be the worst thing you can use to slice through your soil, says Dr. Charles Mitchell, an agronomist with the Alabama Cooperative Extension System.

(Above: Master Gardeners of Cullman County recently conducted experiments as part of a effort to reduce soil compaction problems associated with tillage. Under the direction of Dr. Charles Mitchell, Alabama Cooperative Extension System agronomist, Master Gardeners in Cullman and Lee counties grew several row crops using a variety of alternative tillage techniques. They donated their harvest to local charities and schools.)

Home gardeners till to break up compacted soil. But tilling actually adds to soil compaction, Mitchell says, which leads to more tilling and more compaction. A serious gardener himself, Mitchell decided there had to be a better way of preparing the soil.

After years of research, he and Charles Elkins, a retired soil scientist with the USDA soil dynamics lab in Auburn, discovered there are several alternative tillage techniques that produce a much more effective soil for planting.

Mitchell tested his theory over the past two years by conducting tillage experiments with the help of the Master Gardeners of Cullman and Lee counties. The research was conducted at the North Alabama Horticultural Research Station in Cullman and, most recently, at the E.V. Smith Research Station in Shorter.

"The experiments compared eight different tillage techniques from conventional disking, rototilling and subsoiling to new techniques such as double-digging, slit tilling and no-till," Mitchell said.

The experiments began in 2001 and will continue at least through 2003.

"Most row crop farmers are aware of the consequences of different tillage techniques on soil compaction and root growth," he said. "This is why conservation tillage and subsoiling have been adopted by many producers."

But, Mitchell said, most gardeners and small vegetable farmers are slow to adopt these practices because most gardeners never look deeper than the soil surface, and because many gardeners love to till.

"Gardeners feel like it’s part of the experience of gardening," he said. "They till because they enjoy it. Charles and I got to talking about that one day – about some of the problems

gardeners have and don’t know it. We talked about how soil compaction is a big issue, but most gardeners don’t realize that those fast-turning tillers can compact the soil just like a tractor can. Tillers can actually destroy the soil structure to the point where when it rains on it, it turns to concrete."

The experiments conducted by the Master Gardeners showed that double-digging is actually the best technique. An old technique, double-digging involves digging through the top soil and then breaking through the compacted subsoil without mixing the two layers.

"It’s very labor-intensive," Mitchell said. "But it is absolutely great for the soil. Subsoiling with a tractor is the next best method. It doesn’t destroy the soil structure and breaks up existing hardpans. But since it does require a tractor, the equipment is usually too expensive for gardeners."

The soils in north Alabama don’t compact as badly as the soils in south Alabama, so tillage techniques are not as critical in that part of the state, Mitchell said.

The experiments, which are still being conducted in Cullman, generated a rich bounty. In Cullman alone, about 15 volunteer Master Gardeners put in more than 200 hours on the tillage project. The result was a harvest of almost 2,000 pounds of sweet corn, almost 300 pounds of broccoli and about 550 pounds of cabbage.

The Master Gardeners donated hundreds of pounds of the fresh vegetables to

Cullman County schools, St. Vincent DePaul Food Bank, Childhaven Orphanage and Cullman County Caring For Kids.

Four Lee County Master Gardeners put in about 24 volunteer hours with the project at E.V. Smith. They harvested several hundred pounds of beans, squash and corn and donated it to the East Alabama Food Bank in Auburn.

"We couldn’t have done this without the help of the Master Gardeners," Mitchell said. "This is an excellent way of marrying our research program with our educational program with our local volunteers. It gets our citizens involved with the experiments going on at our research stations and with the Cooperative Extension System."